Modern internal combustion engines typically utilize one or more fuel injectors for metering a precise quantity of fuel to be combusted in respective combustion chambers such that the combustion is initiated with a spark from a spark plug. Combustion of the fuel may be used, for example, to propel a motor vehicle and to generated electricity or drive other accessories in support of operation of the motor vehicle. Fuels in liquid form that are commonly used to power the internal combustion engine include gasoline, alcohol, ethanol, and the like, and blends thereof. Until more recently, fuel injectors commonly referred to as port fuel injectors were predominantly used. Port fuel injectors inject fuel into a port of an intake manifold where the fuel is mixed with air prior to being drawn into the combustion chamber of the internal combustion through an intake valve of the cylinder head. A typical port fuel injector is show in U.S. Pat. No. 7,252,249 to Molnar. The port fuel injector of U.S. Pat. No. 7,252,249; which is typical of port fuel injectors; uses an inward opening valve arrangement which is operated by a solenoid actuator. Fuel that flows past the valve arrangement is metered and shaped by a director plate with holes that are sized and shaped to allow a precise amount of fuel therethrough in such a way as to disperse the fuel into fine droplets which mix with the air.
In order to increase fuel economy and reduce undesirable emissions produced by combustion of the fuel, direct injection fuel injectors have been increasing in use. As the name suggests, direct injection fuel injectors inject fuel directly into the combustion chamber. Direct fuel injectors are commonly available with inwardly opening valve arrangements or outwardly opening valve arrangements. Outwardly opening valve arrangements are desirable due to the hollow cone spray structure that is produced which may include a circumferentially located recirculation zone on the outer perimeter of the hollow cone spray structure which provides a stable site for ignition of the fuel by a spark plug. However, the fuel delivered by outwardly opening direct injection fuel injectors is metered by the distance the valve member is moved from the corresponding valve seat rather than by holes of a director plate. Outwardly opening direct injection fuel injectors have typically required the use of piezoelectric actuators for fast and precise valve actuation which is necessary to precisely meter the fuel and to generate the hollow cone spray structure. While piezoelectric actuators may be effective, they are costly to implement. Advancements in solenoid technology have allowed implementation of solenoid actuators in outwardly opening direct injection fuel injectors; an example of which is shown in United States Patent Application Publication No. US 2011/0163189 A1 to Mancini et al. Even though a solenoid actuator is used, which is less costly than a piezoelectric actuator, the valve components must be made with a high degree of precision which adds to manufacturing costs and complexity. U.S. Pat. No. 8,543,951 to Mieney et al. shows an inwardly opening direct injection fuel injector which includes a nozzle tip with individual holes which are sized and shaped to allow a precise amount of fuel therethrough. Since the fuel is metered by the holes in the nozzle tip, the valve components may be made with a lesser degree of precision than the outwardly opening arrangement. However, the individual holes in the nozzle tip do not allow a beneficial hollow cone spray structure to be produced as is produced by outwardly opening direct injection fuel injectors.
What is needed is an inward opening direct injection fuel injector which minimizes or eliminates one or more of the shortcomings set forth above.